This invention relates to a ball valve for use particularly in subsea hydrocarbon production systems. Although the valve is designed for subsea use, it may also be utilized in other harsh environment applications where a top entry valve is selected to facilitate maintenance operations. The invention also comprises a method for manufacturing an insert assembly for this new ball valve.
In most cases flowlines from subsea hydrocarbon production systems need to include an isolation valve to separate sections of flowlines allowing maintenance of section equipment and emergency shutdown services of flowlines upstream of the process facilities to prevent hazardous pollution/discharges. A primary use of the present ball valve is as such an isolation valve. For use in water depths beyond access of divers the valve insert, which contains all active parts, should be retrievable to the surface for repair by using a remotely operated tool (ROT).
Thus, more particularly the invention is directed to the kind of ball valve comprising a valve body having a cavity of generally conical shape and communicating with inlet and outlet ports having a common axis, an insert assembly provided with a valve ball, two ports corresponding to said inlet and outlet ports, respectively, and associated seat means, the insert assembly has a generally conical shape as cavity and, is adapted to be housed therein and to be retrieved therefrom. The insert assembly is composed of two parts joined together generally along a dividing plane, connector means for releasably fixing said insert assembly in said cavity, and actuator means for rotating the valve ball about its axis between a closed and an open position with respect to the ports.
From U.S. Pat. No. 4,606,368 there is previously known a ball valve for the above purpose, and incorporating features corresponding in part to what is recited immediately above.